Modeling of the source neutrons of D-T neutron generator based on in-situ depth profiling of tritium in the tritide target

摘要

Information on source neutrons is crucial to neutronic experiments that use deuterium-tritium (D-T) neutron generators. The quality of source neutron information affects the reliability of the comparative analysis between experimental and simulated results. Distribution of tritium in the tritide target is a necessary input data for the D-T source neutron analysis. However, due to the lack of an in-situ method, the current parameter analysis of neutron source can only use hypothetical tritium distribution data, which introduces extra uncertainty to the results of modeled neutron source. In this study, we present an in-situ method for profiling tritium in the tritide target based on the measured associated alpha spectra. The developed tritium profiling method can be embedded into the source neutron modeling method so as to obtain the parameters of neutron source. The proposed methodology is validated by measuring the differential spectra of D-T source neutrons at 0°, 45°, 90°, 135°, using the time of flight (TOF) method. At these angles, the neutron intensity ratios of the simulation to the experiment are 1.04 ± 4%, 1.08 ± 2%, 0.90 ± 2%, 1.04 ± 3%; while the difference of the peak energy between measured and calculated spectra are 0.05 ± 0.01 MeV, 0.12 ± 0.04 MeV, 0.24 ± 0.06 MeV, and 0.25 ± 0.01 MeV, respectively. It is found that measured and simulated results are in good agreement in terms of neutron intensity and peak energy; and that further investigation is required to understand the discrepancy on the differential spectra obtained in simulation and measurement.